MIPS: remove immediate constraint within CompareAndSwap.

src/base/atomicops_internals_mips_gcc.h

Index: src/base/atomicops_internals_mips_gcc.h
diff --git a/src/base/atomicops_internals_mips_gcc.h b/src/base/atomicops_internals_mips_gcc.h
index d33b66876b96cfeb574141a2a7ec755aa333bf98..442fdd0f96a1d30a3f824d06e0328fb6433897d3 100644
--- a/src/base/atomicops_internals_mips_gcc.h
+++ b/src/base/atomicops_internals_mips_gcc.h
@@ -36,7 +36,7 @@ inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
                        "2:\n"
                        ".set pop\n"
                        : "=&r" (prev), "=&r" (tmp)
-                       : "Ir" (old_value), "r" (new_value), "r" (ptr)
+                       : "r" (old_value), "r" (new_value), "r" (ptr)
                        : "memory");
   return prev;
 }